typedef struct Node {
    Node* next;
    int data;
} LinkList;


double Ratio(LinkList* head) {
    LinkList* temp = head->next;
    if (!temp) {
        return -1.0;
    }
    double c1 = 0;
    double c2 = 0;
    while (temp) {
        if (temp->data > 0) {
            c2 = c2 + 1;
        }
        c1 = c1 + 1;
    }
    return c1 / c2;
}